feat: caching & logging

backend/logger.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"log/slog"
+	"os"
+	"strconv"
+
+	"DownLink/services"
+)
+
+// Global log buffer for API access
+var LogBuffer *services.LogBuffer
+
+// setupLogger configures structured logging for the application
+func setupLogger() {
+	// Get log level from environment variable, default to INFO
+	logLevel := slog.LevelInfo
+	if levelStr := os.Getenv("LOG_LEVEL"); levelStr != "" {
+		switch levelStr {
+		case "DEBUG":
+			logLevel = slog.LevelDebug
+		case "INFO":
+			logLevel = slog.LevelInfo
+		case "WARN":
+			logLevel = slog.LevelWarn
+		case "ERROR":
+			logLevel = slog.LevelError
+		}
+	}
+
+	// Initialize log buffer (store last 1000 logs)
+	bufferSize := 1000
+	if sizeStr := os.Getenv("LOG_BUFFER_SIZE"); sizeStr != "" {
+		if parsed, err := strconv.Atoi(sizeStr); err == nil && parsed > 0 {
+			bufferSize = parsed
+		}
+	}
+	LogBuffer = services.NewLogBuffer(bufferSize)
+
+	// Get log format from environment variable, default to JSON
+	logFormat := os.Getenv("LOG_FORMAT")
+	var baseHandler slog.Handler
+
+	if logFormat == "text" {
+		baseHandler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+			Level: logLevel,
+		})
+	} else {
+		// Default to JSON format
+		baseHandler = slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+			Level: logLevel,
+		})
+	}
+
+	// Wrap the base handler with in-memory handler
+	handler := services.NewInMemoryHandler(LogBuffer, baseHandler)
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+
+	slog.Info("Logger initialized",
+		"level", logLevel.String(),
+		"format", logFormat,
+		"buffer_size", bufferSize,
+		"service", "DownLink Backend")
+}